Petersen's Heart Ailment Halts CSI

Things are not entirely back to normal on the set of CBS's top-rated CSI: Crime Scene Investigation, which last week was rocked by the firings – and subsequent re-hirings – of costars George Eads and Jorja Fox, who were both reportedly demanding a salary hike.

The latest snag involves series lead William L. Petersen, who did not show up for the first day of filming for fifth season because of a recently diagnosed heart condition, reports the Los Angeles Times.

The actor, 51, notified CBS before shooting began that he would miss the first few days of work because of the condition. Petersen's rep, confirming that his client was dealing with "health-related matters," did not offer specifics.

According to CBS, Petersen was expected to return to work by Wednesday, along with Eads and Fox.

"Billy and the rest of the cast are expected back on the set this Wednesday," said network spokesman Chris Ender. "Everyone is excited to resume production and get started on the fifth season."

Petersen, who has been seeking a pay hike, earns an estimated $350,000 per episode, including a producer's fee, for the show. Two years ago, once the success of the show was assured, he received a substantial salary boost.

His absence, the Times reports, is by no means a "sickout" in an effort to re-negotiate his contract.